[BRIEF NOTE] On the possible non-existence of Alpha Centauri Bb

[rfmcdonald]

I've a minor attachment to Alpha Centauri Bb, not only because I played a minor role in breaking the ESO's press embargo on the nearest exoplanet discovered so far, but because Alpha Centauri is cool: next-door, Sun-like, a long-standing feature of popular culture. That's why I'm just a bit sad to learn that, as described by the New York Times' Dennis Overbye, there are suggestions that the discovery was mistaken.

Writing in The Astrophysical Journal last month, Artie P. Hatzes, the director of the Thuringian State Observatory in Tautenburg, Germany, who was not part of the original discovery team, reported that he could not confirm the planet when he went looking for it in the European data on his own. “Sometimes it is there, other times not,” depending on the method he used to reduce the statistical noise, he said in an e-mail.

That doesn’t mean the planet does not exist, Dr. Hatzes wrote, but “in my years of experience in extracting planet signals, this simply does not ‘smell’ like a real planet.”

Dr. Hatzes’s skepticism proved catching. Suzanne Aigrain of Oxford University quoted Carl Sagan’s dictum that extraordinary claims require extraordinary evidence, saying that Dr. Hatzes’s paper “certainly casts doubt on the original evidence.”

Xavier Dumusque of the University of Geneva, who led the original discovery effort, said that Dr. Hatzes’s challenge was healthy for science. “Calling to question a detection is always something fruitful,” Dr. Dumusque wrote in an e-mail. But he added that it was clear in his team’s paper that “the signal we are searching for is at the limit of the data precision.”

More data, everyone agrees, is essential, and luckily there will be more data, according to Debra Fischer, a Yale astronomer who has studied the Alpha Centauri system. Both her group and the Geneva team of which Dr. Dumusque is a member obtained more observations in May.

Hatzes' paper is available here.